1. Field of the Invention
This invention relates to the field of processing and packaging consumer products, particularly in the pharmaceutical industry. More specifically, this invention relates to an improved apparatus and method for applying a heat shrinkable sleeve to a container such as a vial for pharmaceuticals that is safer, more efficient, and more precise than other systems and methods that have been used for such purposes in the past.
2. Description of the Prior Art
In most instances, containers that are used to hold a consumer product such as a medicament need a label to specifically identify the goods contained therein. In addition, to protect consumers, manufacturers of over the counter pharmaceuticals and certain types of foods and beverages often provide a tamper evident seal in their packaging which becomes permanently broken or ruptured when the container is first opened.
Frequently, a label itself is used as a tamper evident seal by adhering portions of the label to two or more relatively displaceable components of the packaging. For example, a tamper evident seal can be achieved in a vial that has a removable cap by adhering portions of a label to both the body of the vial and the removable cap.
In practice, the most efficient way to apply a label or tamper evident sleeve to many containers is to place a heat shrinkable sleeve or label about the container, and then to shrink the sleeve or label against the container by passing both the sleeve or label and the container through a heat tunnel apparatus. For small containers such as pharmaceutical vials, though, it is often difficult to ensure that the sleeve or label shrinks uniformly around the periphery of the vial. Non-uniform shrinkage presents a problem, particularly when it is a label that is being applied, because it can cause distortion of printed messages and designs which appear on the labelling. In view of government regulations, concern for the consumer and quality control standards, most pharmaceutical marketers will not tolerate such deviations in product labelling.
Another problem with heat shrinkable labelling is that the heat tunnel apparatus that is used to apply the labelling can malfunction, possibly resulting in damage to the products or in an otherwise dangerous situation.
A long and unfilled need in the prior art exists for a system for applying a heat shrinkable sleeve or label to a container such as a vial for pharmaceuticals which reduces distortion and unwanted displacement of the sleeve or label during its application, and which prevents product damage or other dangerous situations from developing as a result of a malfunction of a heat tunnel apparatus.